1. Field
Example embodiments generally relate to a separation device, a fixing device, and an image forming apparatus, and more particularly, to a separation device for separating a recording medium from a rotary body and a fixing device and an image forming apparatus incorporating the separation device.
2. Discussion of the Background
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, or multifunction printers having two or more of copying, printing, scanning, facsimile, plotter, and other functions, typically form an image on a recording medium according to image data. Thus, for example, a charger uniformly charges a surface of a photoconductor; an optical writer emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a development device supplies toner to the electrostatic latent image formed on the photoconductor to render the electrostatic latent image visible as a toner image; the toner image is directly transferred from the photoconductor onto a recording medium or is indirectly transferred from the photoconductor onto a recording medium via an intermediate transfer belt; finally, a fixing device applies heat and pressure to the recording medium bearing the toner image to fix the toner image on the recording medium, thus forming the image on the recording medium.
Such fixing device may include a fixing rotary body such as a fixing roller and a fixing belt and a pressing rotary body such as a pressing roller and a pressing belt pressed against the fixing rotary body to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. As the fixing rotary body and the pressing rotary body rotate and convey the recording medium through the fixing nip, the fixing rotary body and the pressing rotary body apply heat and pressure to the recording medium, melting toner of the toner image and fixing the toner image on the recording medium.
Since toner is made of resin, as it is melted at the fixing nip, it may adhere to the fixing rotary body. To address this circumstance, various configurations are proposed. For example, a separation pawl may be disposed opposite the fixing rotary body to separate the recording medium from the fixing rotary body and therefore prevent adhesion of toner of the toner image from the recording medium to the fixing rotary body. However, as the separation pawl separates the recording medium from the fixing rotary body, the toner image on the recording medium may come into contact with the separation pawl.
Since the separation pawl is situated in proximity to the fixing nip, the toner image on the recording medium may come into contact with the separation pawl before toner of the toner image melted while the recording medium passes through the fixing nip has been cooled. When the toner image melted and softened at the fixing nip comes into contact with the separation pawl, the toner image is subject to damage. For example, if a recording medium conveyance face of the separation pawl over which the recording medium slides is rough, the rough face may scratch the softened toner image, degrading the toner image into a streaky toner image. Conversely, if the recording medium conveyance face of the separation pawl is excessively smooth, the melted toner of the toner image may be subject to adhesion to the separation pawl, increasing frictional resistance between the toner image on the recording medium and the separation pawl and hindering conveyance of the recording medium.
To address this circumstance, a center separation pawl and lateral end separation pawls may be disposed opposite the fixing rotary body to separate the recording medium from the fixing rotary body. The lateral end separation pawls project beyond the center separation pawl toward the recording medium. However, as the recording medium bearing the toner image is discharged from the fixing nip, the recording medium may contact the lateral end separation pawls with increased pressure therebetween, producing a sharp streak on the toner image on the recording medium.